The present invention relates to rack-mountable modular electronic circuits, and is primarily concerned with providing a supporting element for a circuit card such as a sound modem or graphics card mounted in a modular circuit housing. Specifically, the invention is concerned with a support element movable on a rail to engage cards of different dimensions.
In electronic circuits such as computers and servers, a motherboard supports the main processing components and provides electrical connections thereto and to ancillary components such as power supplies, disc drives etc. The motherboard is often also provided with xe2x80x9cexpansion slotsxe2x80x9d, which are edge connectors electrically connected to the motherboard wiring and into which circuit boards may be inserted to augment the functionality of the circuit. Sound cards, graphics cards and modems are examples of the circuit boards which may be put into the expansion slots.
Since the cooling components of the circuit generate mechanical vibration, the service life of the expansion boards is increased if the boards are supported both at their edge connector and at a point remote from the edge connector. This multi-point support reduces the vibrational flexing of the circuit board and prevents damage to components and wiring tracks caused by flexing.
Expansion boards are commercially produced in different sizes, and thus to effectively support any of the boards which may be put into an expansion slot it is necessary to arrange for a support at one of a number of different locations relative to the edge connector. A solution to this problem is to provide a rail along which a support may be moved to suit the dimensions of the expansion board, and a clamp arrangement to clamp the support at the required position. However, the vibration which necessitates the support also can loosen the clamp and lead to unwanted movement of the support and the expansion board.
An aspect of the present invention provides a support assembly for a circuit board wherein a support element is movable along a support rail and is selectively fixable at one of a plurality of fixing points along the rail by engagement of a detent on the support element and a longitudinally-facing abutment surface on the rail.
Another aspect of the invention provides a support assembly wherein a rail has a plurality of recesses spaced along its length and the support element has a bolt engageable with a selected one of the recesses to fix the support element in a longitudinal position relative to the rail. In one particular embodiment, the bolt is resiliently biased toward an extended, recess-engaging, position and is manually retractable to a released position.
Another aspect of the invention provides a housing for an electronic circuit wherein the housing comprises a support rail having number of longitudinally-facing abutment surfaces.
Further aspects provide a rack-mountable circuit module having such a housing, and a rack-mounted electronic circuit consisting of a number of such modules.